Differences between patient- and professional-reported modified Rankin Scale score in patients with unruptured aneurysms

OBJECTIVE Clinical trials forming the basis of current guidelines for the management of intracranial aneurysms have relied on patient-reported modified Rankin Scale (mRS) scores to assess functional outcome. The effect of patient demographics on perception of disability and, by extension, patient-reported mRS score, is not well understood. METHODS A consecutive series of patients with a previously treated or untreated unruptured intracranial aneurysm (UIA) prospectively underwent a structured interview with a trained nurse. At the conclusion of this interview, the patients were assigned an mRS score in accordance with their degree of disability. During the same visit, patients were also required to grade themselves on a paper sheet containing the mRS and corresponding information. Data on patient and aneurysm characteristics were also collected during the same visit. Agreement between patient- and nurse-reported mRS scores was assessed using Cohen’s kappa coefficient. The effect of patient demographics on the frequency of higher patient- than nurse-reported mRS scores was assessed using the Pearson’s chi-square and Fisher’s exact tests. RESULTS A total of 209 patients with a UIA were included in the study, 38 of whom (18.2%) had undergone previous treatment. The majority of patients were female (161/209, 77.0%), and the mean age of the cohort was 60.2 years (SD 13.7 years). Agreement between patient- and nurse-reported mRS scores occurred in 72.7% of cases (95% CI 66.3%–78.3%), with a kappa coefficient of 0.58 (95% CI 0.49–0.67). Patients younger than 75 years were more likely to report a higher mRS score than the nurse (19.4% vs 3.4%, p = 0.034). Among female patients, those without a college degree were more likely to report a higher mRS score than the nurse (22.5% vs 9.5%, p = 0.035). CONCLUSIONS The results suggest that patient demographics may influence perception of disability. These findings should be considered when using patient-reported mRS scores to determine functional outcome.